Horton

Re: [HACKERS] WAL logging problem in 9.4.3?

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: robertmhaas@gmail.com, pgsql-hackers@postgresql.org, 9erthalion6@gmail.com, andrew.dunstan@2ndquadrant.com, hlinnaka@iki.fi, michael@paquier.xyz
Date: 2020-01-27T04:22:01Z
Lists: pgsql-hackers 
Diffing the two latest versions of one patch:
> --- v32-0002-Fix-the-defect-1.patch	2020-01-18 14:32:47.499129940 -0800
> +++ v33-0002-Fix-the-defect-1.patch	2020-01-26 16:23:52.846391035 -0800
> +@@ -2978,8 +3054,8 @@ AssertPendingSyncs_RelationCache(void)
> + 			LOCKTAG_RELATION)
> + 			continue;
> + 		relid = ObjectIdGetDatum(locallock->tag.lock.locktag_field2);
> +-		r = RelationIdGetRelation(relid);
> +-		if (r == NULL)
> ++		r = RelationIdGetRelationCache(relid);

The purpose of this loop is to create relcache entries for rels locked in the
current transaction.  (The "r == NULL" case happens for rels no longer visible
in catalogs.  It is harmless.)  Since RelationIdGetRelationCache() never
creates a relcache entry, calling it defeats that purpose.
RelationIdGetRelation() is the right function to call.

On Tue, Jan 21, 2020 at 06:45:57PM +0900, Kyotaro Horiguchi wrote:
> Three other fixes not mentined above are made. One is the useless
> rd_firstRelfilenodeSubid in the condition to dicide whether to
> preserve or not a relcache entry

It was not useless.  Test case:

  create table t (c int);
  begin;
  alter table t alter c type bigint;  -- sets rd_firstRelfilenodeSubid
  savepoint q; drop table t; rollback to q;  -- forgets rd_firstRelfilenodeSubid
  commit;  -- assertion failure, after s/RelationIdGetRelationCache/RelationIdGetRelation/ discussed above

Commits

  1. Add perl2host call missing from a new test file.

  2. Skip WAL for new relfilenodes, under wal_level=minimal.

  3. Revert "Skip WAL for new relfilenodes, under wal_level=minimal."

  4. Back-patch log_newpage_range().

  5. During heap rebuild, lock any TOAST index until end of transaction.

  6. In log_newpage_range(), heed forkNum and page_std arguments.

  7. Back-patch src/test/recovery and PostgresNode from 9.6 to 9.5.

  8. Reduce pg_ctl's reaction time when waiting for postmaster start/stop.

  9. Accelerate end-of-transaction dropping of relations

  10. Redesign the planner's handling of index-descent cost estimation.

  11. Make TRUNCATE do truncate-in-place when processing a relation that was created